AUSTIN – Both an engaging character study and a useful introduction to issues surrounding biodiversity, Sandy McLeod's Seeds of Time explains why scientist Cary Fowler thinks it's so important to preserve hundreds of plant varieties that commercial farms have no interest in growing. While the accessible and handsome film is less grabby than more sensationalistic eco-docs, it has a broad enough appeal to draw attention beyond the fest circuit and, hopefully, to generate some offscreen interest in seed-saving.

Fowler, a curly-headed Tennessean who has made crop diversity his life's work, acknowledges that his passion for the issue has played "a sizeable role in the demise of two marriages." If that sounds like an extreme sacrifice for the preservation of species whose yields don't meet the demands of industrial farming, he might argue, you just don't understand the issue. In a world where millions of acres might be devoted to growing a single variety of wheat, one new crop disease could lead to starvation on a global scale.

The film follows Fowler around the world as he speaks at conferences and adds to the collection of seeds at Svalbard, Norway's "frozen garden of Eden" -- a bunker just 810 miles from the North Pole, where sub-freezing temperatures can keep specimens viable for replanting thousands of years from now. But while it introduces us to this hugely ambitious and expensive project, it also recounts the history of "seed-saving," paying particular attention to Russian botanist Nikolai Vavilov, whose workers were so convinced of the value of preserving specimens they refused to eat samples that could have saved their lives during the Siege of Leningrad. Less dramatic but sometimes heart-wrenching calamities have wiped out some modern seed banks, as we learn in meetings Fowler has with peers who run usually underfunded operations in faraway countries.

Appealing in a different way is a long section set in Peru, where different communities of indigenous people rely on varieties of potato for both food and cultural ceremonies. Forming an unusual alliance, they cooperate to plant a "potato park" in which as many varieties as possible are nurtured -- helping the mountain-dwellers prepare for climate change-driven die-offs that are already happening.